HYDRAULIC CONDUCTIVITY OF CELL-WALLS IN SUGAR-BEET TISSUE

Parenchymal tissue from sugar beet tap root (Beta vulgaris) was investigated. After destruction of the cell membranes by heat or action of tetrachloromethane, the tissue is shown to be highly compressible, The water flow proceeds exclusively from a zone adjacent to the outflow surface while no flow takes place in the remaining part of the tissue. During the dewatering process this zone increases until the total probe is compressed. Subsequently a further dewatering (consolidation period) is observed. The first period is equivalent to a filtration. By transferring the filtration theory to the compression of cells both the overall hydraulic conductivity L(p) and the specific hydraulic conductivity of the cell wall material L(pp) can be calculated. The value L(pp) almost-equal-to 10(-3) cm2 bar-1 s-1 is one order of magnitude higher than that postulated by Steudle and Boyer for soy bean tissue. The role of the intercellular space is not yet elucidated.